Unnamed (ridge northeast of Spruce Peak)

Occurrence, Inactive

Commodities and mineralogy

Main commodities Fe
Other commodities Ag; Au
Ore minerals limonite; pyrite
Gangue minerals feldspar; quartz

Geographic location

Quadrangle map, 1:250,000-scale MM
Quadrangle map, 1:63,360-scale C-2
Latitude 63.5975
Longitude -150.6661
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is at an elevation of about 4100 feet on an unnamed ridge between upper Myrtle Creek and upper Caribou Creek. It is about 1.4 miles north of Spruce Peak, in the NE1/4 SW1/4 section 21, T. 15 S., R. 16 W., Fairbanks Meridian. The location is accurate within 500 feet. The occurrence corresponds to number 59 of Bundtzen, Smith, and Tosdal (1976), 277 of Hawley and Associates (1978), and 66b of Bundtzen (1981).

Geologic setting

Geologic description

This occurrence is a stratabound gossan developed on pyritic metafelsite of the lower Paleozoic Spruce Creek sequence (Bundtzen, 1981). The metafelsite forms stratiform lenses in graphitic and chloritic schist. The gossan can be traced southwesterly for about 1500 feet. As much as 50 percent pyrite occurs in half-inch-thick bands in the metafelsite; much of this material is oxidized to limonite. Samples contain less than 1 ppm each of gold and silver, and small amounts of copper, lead, and zinc (Thornsberry, McKee, and Salisbury, 1984, v. 2).
Geologic map unit (-150.668385237996, 63.5970006442742)
Mineral deposit model Stratabound deposit in metafelsite.
Age of mineralization Probably early Paleozoic, the protolith age of the Spruce Creek sequence.
Alteration of deposit Iron-oxide alteration.

Production and reserves

Workings or exploration Reconnaissance mapping and sampling. There are no workings.
Indication of production None

Additional comments

The occurrence is in Denali National Park and Preserve.

References